RESUMO
Folate deficiency during pregnancy has been related to low birth weight, preterm (PT) birth and other health risks in the offspring; however, it is unknown whether prematurity is related to low folate transport through the placenta due to altered expression of specific folate transporters. We determined placental expression (mRNA and protein concentrations by RT-qPCR and WB respectively) of specific folate transporters: RFC, PCFT/HCP1 and FOLR1 in chorionic (fetal) and basal (maternal) plates of placentas of PT pregnancies (PT, 32-36 weeks, n = 51). Term placentas were used as controls (T, 37-41 weeks, n = 47). Folates and vitamin B12 levels were measured by electrochemiluminescence in umbilical cord blood of newborns. FOLR1 mRNA expression was lower and protein concentration higher in PT placentas (both plates) relative to the control group (p <0.05). In addition, gestational age was positively correlated with mRNA expression (Rho = 0.7), and negatively with protein concentration (Rho = -0.7 for chorionic and -0.43 for basal plate). PCFT/HCP1 mRNA was lower in PT placentas, without changes in protein levels. RFC did not differ in PT placentas compared to controls. PT newborns presented higher cord blood folate level (p = 0.049) along with lower vitamin B12 concentration compared to controls (p = 0.037).In conclusion, placental FOLR1 mRNA was positively associated with gestational age. Conversely, FOLR1 protein concentrations along with folate/vitamin B12 ratio in cord blood were negatively associated with gestational age. Placental FOLR1 is likely the main placental folate transporter to the fetus in newborns.
Assuntos
Sangue Fetal/metabolismo , Transportadores de Ácido Fólico/metabolismo , Ácido Fólico/sangue , Placenta/metabolismo , Vitamina B 12/sangue , Adulto , Feminino , Receptor 1 de Folato/genética , Receptor 1 de Folato/metabolismo , Transportadores de Ácido Fólico/genética , Humanos , Recém-Nascido , Recém-Nascido Prematuro , Gravidez , Nascimento Prematuro/sangue , Nascimento Prematuro/genética , Nascimento Prematuro/metabolismo , Transportador de Folato Acoplado a Próton/genética , Transportador de Folato Acoplado a Próton/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína Carregadora de Folato Reduzido/genética , Proteína Carregadora de Folato Reduzido/metabolismo , Nascimento a Termo/sangue , Nascimento a Termo/genética , Nascimento a Termo/metabolismo , Adulto JovemRESUMO
BACKGROUND: Adequate folate levels are essential for successful pregnancy outcomes. We aimed to study the relationship between placental mRNA and protein levels of folate transporters to birth weight. METHODS: Placental folate transporters (FOLR1, RFC1 and HCP1/PCFT) mRNA and protein levels in basal (BP) and chorionic plate (CP) of small (SGA), appropriate (AGA) and large (LGA) for gestational age term infants (≥37 weeks gestation, n = 111) were determined by real-time PCR and Western blot respectively. RESULTS: FOLR1 and HCP1/PCFT mRNA were lower in both plates of SGA and LGA placentas compared to AGA (p < 0.01) and RFC1 mRNA was lower only in CP (p < 0.02). RFC1 protein levels were lower in BP of SGA (p < 0.05) and LGA (p < 0.01), and FOLR1 protein levels were lower in CP of SGA (p < 0.02) and LGA (p < 0.01) groups compared to AGA. HCP1/PCFT protein levels remained unchanged in all groups. CONCLUSION: Placentas of SGA and LGA groups showed a reduced mRNA expression and protein levels of folate transporters, with some differences depending on the location within the placenta (BP or CP). This suggests the presence of specific placental regulation mechanisms in gene expression that may be associated to birth weight.
